The present invention relates to an error correcting decoder for correcting code error caused by transmission or accumulation of a digital code.
Conventionally, error correcting decoders for decoding of a variable parameter block unit changes an encoding parameter by changing computations inside the decoder. Therefore, changing the encoding parameter of error correcting decoder is possible to a period lacking data during processing inside the decoder.
In data communications based on a variable length packet, usage efficiency of a line and noise tolerances are increased simultaneously by changing the parameter for error correction encoding according to the length of data frame. In order to realize such operation, information about frame length and the error correcting encoding parameter for use are previously adjusted in a transmission node and a receiving node and the error correcting encoding parameter may be changed according to the frame by changing the error correcting encoding parameter for every time of frame arrival.
However, it is restricted that the conventional error correcting encoder and the error correcting decoder, of which encoding parameters are variable, require a certain time for completion of encoding and decoding, and encoding parameters cannot be changed during the time. Therefore, performing error correction encoding processing and error correction decoding processing of a signal of which encoding parameters are frequently changed, particularly, performing error correction encoding processing and error correction decoding processing are difficult for a signal in which error correction encoding blocks of various encoding parameters arrive at the decoder with very small time intervals.
Different error correcting encoding parameters generally causes a change of processing time for error correction encoding and error correction decoding. Therefore, an output generated from an input, which has a mixture of error correction encoding blocks of various encoding parameters, subjected to error correction encoding end error correction decoding has a problem such that an order of encoding blocks is incorrectly outputted and that times for outputting a certain encoding block and other encoding blocks before and after overlap causing an abnormal output.
It is an object of the present invention to realize a function to perform error correction decoding of a signal of which encoding parameters change, particularly, a function to perform error correction decoding of a signal of which error correction encoding blocks of various encoding parameters arrive at the decoder with very small time intervals.